James Clark, author of Expat, for having provided very useful guidance on the proper way to design and implement a highly reusable C library. 

Apache Project's 
----------------
Apache Axis2 [http://ws.apache.org/axis2]   - Initial Architecture
Apache Maven [http://maven.apache.org/]     - Site generation.
Apache APR   [http://apr.apache.org/]       - Versioning Guideline, Some codes in util
Apache HTTPD [http://httpd.apache.org/]     - mod_axis2